Xenon headlights have been around for quite a while now, you would certainly have heard them mentioned at some point. You probably know that they are somehow ‘better’ than regular old halogen headlights, but not exactly why that is.

In this guide we will cover in depth how they work, what superior qualities they possess as well as various other pros and cons. After reading you should have no unanswered questions and be able to decide whether fitting xenon headlights to your vehicle is worth it.

What are xenon headlights?

Stock headlights use conventional bulbs that rely on halogen gas. Xenon headlights, on the other hand, forgo halogen for xenon. This gas emits a much brighter white light than halogen. Alternatively, xenon headlight bulbs are sometimes called high-intensity discharge (HID lights). The first car manufacturer to utilize xenon headlights was BMW. They used xenon bulbs for their 7-series sedans. Predictably, many other carmakers followed suit and ditched halogen.

Xenon Headlights Comprise:

Discharge Lamp

This stores xenon gas and several other gases too. When the lamp is electrified, it produces its signature bright, intense white light for which xenon headlights are famed. This part of the xenon HID system holds the electricity discharging electrodes.

Xenon Ballast

This is the device responsible for igniting the gaseous mix inside a xenon bulb. Fourth-gen HID headlights can produce as much as 30 kV pulses of high voltage. The xenon ballast regulates the activation to ensure the bulb reaches optimum operation quickly. Once at optimum brightness, the ballast manages the power flow to maintain a steady and even brightness. Inside this component is a DC converter. This allows the xenon ballast to produce the necessary voltage to power the bulb and all the other components. The ballast is also fitted with a bridge circuit that supplies the HID system with 300 Hz of alternating voltage.

Ignition Module

As is suggested by the name, the ignition module triggers the ‘spark’ required. The ignition module is connected to the previously mentioned xenon ballast component. Depending on which generation the HID system is, the ignition module may have metal shielding as well.

How do xenon headlights work?

First, let’s consider how traditional halogen works. In these standard headlights, electricity is passed through tungsten filaments inside the bulbs. As the bulbs are filled with halogen gas, it reacts with the tungsten filaments. The gas helps to heat the filaments, allowing them to glow.

HID xenon headlights work in a completely different manner. To begin with, they don’t contain a filament. Instead, the xenon gas contained within the bulb is ionized.

In essence, there are three steps involved in getting xenon headlights to work correctly. These are:

Ignition

When you turn on xenon headlights, electricity is sent to the bulb’s xenon ballast and electrodes. Together, they ignite and ionize the xenon gas while simultaneously acting as a ‘bridge’ for the electrodes.

Heating

This ionization of the gas mix within the bulb causes the temperature to rise rapidly. As this occurs, there is a matching drop in the amount of resistance between the bulb’s electrodes.

Brightness

A steady flow of around 35W is supplied to the bulb by the xenon ballast. This consistent electrical supply enables the bulb to operate at optimum efficiency and produce intense white light.

However, bear in mind that the xenon gas is only used as a trigger. Once the other gases get ionized, they replace the xenon and produce the bright illumination. It can take a little while – sometimes a few seconds – before an HID system’s trademark brightness kicks in.

Benefits Provided by xenon Headlights

You will see several benefits by switching from halogen to HID xenon headlights.

More Natural, Brighter Light

With a rating of 35W, a xenon bulb is capable of producing as much as 3,000 Lumens. A comparable halogen bulb of the same wattage can only manage 1,400 Lumens. A halogen bulb also emits a yellow/white light. The color temperature of a xenon bulb, by comparison, is much closer to that of natural daylight.

Wider Coverage

In addition to being brighter and resembling natural daylight, an HID xenon system’s illumination penetrates down the road much further. As HID headlights produce longer reach than conventional halogen bulbs, night time driving is considerably safer.

Better Energy Efficiency

Though a xenon bulb needs more initial energy, they run frugally during operation and consume far less energy than the equivalent halogen bulb. They are overall more energy-efficient, but the difference is too minor to be readily noticeable.

Longer Lasting

The average halogen bulb will work for approximately 400 to 600 hours. Xenon HID, conversely, will easily reach up to 5,000 hours. Even so, it still trails miles behind LEDs, which have a lifespan of 25,000 hours.

Disadvantages

Though xenon headlights are notable for their near daylight illumination, it has to be offset against some significant drawbacks.

Expense

They cost substantially more than halogen bulbs. Though costing less than LED headlights, the lifespan of LEDs means you will be replacing your HID lights five times as often.

Glare

The very intense light generated can incur the wrath of oncoming traffic. The intense glare dazzles other drivers and could potentially cause an accident.

Retrofitting Can be a Challenge

If you want to replace existing halogen headlights with an HID system, retrofitting can be a challenging task. Retrofit xenon kits are widely available, but it is not a five-minute job. You will need to have at least some basic auto-electronics knowledge to set up xenon headlights correctly.

Needs Time to ‘Heat Up’

Halogen headlights are instantaneous and provide full brightness as fast as you switch them on. However, a xenon system requires some seconds to ‘heat up’ and reach their optimum performance capacity.

For sure, xenon headlights are in high demand today simply because of their power and brightness. In common with every other lighting system currently on the market, the HID system has its share of positive and negative points. Each of these factors has to be considered when determining if xenon headlights are the right route to take for you.